The Red Admiral is a common and very familiar migrant butterfly that in recent decades has begun to survive the British winters. It is a frequent visitor to garden Buddleias and its caterpillars feed on Stinging Nettle (Urtica dioica). (For further details on this species see http://www.butterfly-conservation.org/).

Log collated index plot

This chart shows the index of abundance (LCI = Log Collated Index) over time. It shows fluctuations in
populations from year to year, and is scaled so that the average index over the whole series is equal to 2
(horizontal line). For greater detail about how this index is derived, click on the green question mark above.

Trend description :This species has shown a largely steady and highly significant increase over the monitoring period. Analysis of the data indicates that this is largely due to increased immigration rather than increased overwintering or breeding success, as there is no correlation between numbers recorded the previous summer and autumn and those recorded the following spring. However, with a warming climate Red Admiral is likely to overwinter more and more regularly in the UK with the distribution at which this occurs also moving northwards.

Phenology plot

Phenology plot

This chart shows the average number of butterflies seen on transects between Arpil and October across all sites (fitted values from a Generalised Additive Model). The blue line gives average counts over the full BMS series (1976 to date) and the red line gives the average for the last year.

This map shows symbols for the mean abundance at transect sites, with the colour of the symbol reflecting the level of abundance. Means are over all years. Grey background squares are the occupied cells as shown by the Butterflies for the New Millenium over the previous ten year period.

Coverage

In total, Red Admiral has been recorded from 877 transects in the Butterfly Monitoring Scheme. Of these, annual indices of abundance have been calculated from 1034 sites, with an average index of 13 individuals per site.

For 490 of these sites, Red Admiral has been recorded well enough to calculate annual indices of abundance in more years, allowing trends to be calculated.

In 2017, 13814 individuals were recorded from 638 sites, producing annual indices at 499 of these.

This map shows the trend in abundance at particular transect sites for which data has been received within the last five years. Trends (increasing, declining or stable) are assessed at sites where the species has more than five years of annual index data. Use the option boxes below to view plots for individual sites.